Meet Polypane, a Browser That Makes You Five Times Faster...When you open Polypane, you don’t see just a website. You see your website at multiple screen sizes at the same time, just as if you had a bunch of devices on your desk. What’s better, though, is that all these screen sizes are synced: if you interact with one you interact with all of them, whether you’re scrolling, clicking, hovering or typing. You’re interacting with a single website; you just happen to see it at multiple sizes at the same time...
NOTE: there is a trial period and then you have to pay for it.
